As solid state imaging devices (e.g., a CMOS image sensor), there are two types, i.e., a front side illumination type (an FSI type) and a back side illumination type (a BSI type).
In the front side illumination type, a back gate electrode is provided on an entire back surface of a semiconductor substrate, and a potential can be supplied to the semiconductor substrate from this back gate electrode. However, in recent years, to solve a problem of a reduction in sensitivity involved by high pixilation, the back side illumination type, the sensitivity of a light receiving portion thereof of which is not affected by a wiring layer, is becoming mainstream.
In the back side illumination type, since color filters are provided on the back surface of the semiconductor substrate, a potential cannot be supplied to the semiconductor substrate from the back surface side of the semiconductor substrate. Therefore, an electrode configured to supply a potential to the semiconductor substrate is necessarily partially provided on a front surface side of the semiconductor substrate on which the wiring layer is provided. However, since the semiconductor substrate has a large resistance, it is difficult to stabilize the potential in the semiconductor substrate by this configuration alone.